Carburetor



w/B. BRONANDER Feb. 11, i930.

Patented Feb. 11,- 1930 PATENT OFFICE WILHELM B. BRONANDER, OF NEWARK, NEW JERSEY CARBURETOR Application led October 31, 1924. Serial No. 746,976.

This invention relates to carburetors for internal combustion engines.

@ne serious problem that has been encountered in the design of carburetors is to provide a rich mixturewhen the engine is opened up or when -a burst of speed is desired and to provide a leaner' mixture for the. engine when the engine has been speeded upon and is running at high speed. With the ordinary type of carburetor if the engine operator attempts to rapidly accelerate the engine,` a mixture will be fed to the engine that has much too large a proportion of air or, in other words, is too lean. Furthermore, with the usual type if the carburetor is adj usted tov give the desired richness of mixture for acceleration, the mixture will be maintained too rich or richer than necessary for the operation of the engine after the engine o is running at high speed.

With the above problems in mind, this invention has for its salient object to design a carburetor so constructed and arranged as to provide the proper amount and grade of combustible mixture to an engine under all conditions of operation thereof.

Another object of the invention is to provide a carburetor so constructed and arranged that a rich mixture will be available for accelerating or speeding up the engine and a leaner mixture will be supplied after the engine has been speeded up and is running at high speed.

Another object of the invention is to provide a carburetor so constructed and arranged `that a rich mixture will be available for acceleration purposes and the mixture will be automatically controlled and made lean after the engine has been speeded up and, furthermore, a carburetor having an idling jet and pear from the following specification taken in yconnection with the drawings, which form a part of this application, and in which Fig. l is a sectional elevation of a carburetor constructed in accordance with the invention.

2 is an enlarged sectional elevation showing the needle valve for automatically controlling the quantity of fuel fed to the auxiliary carburetor jet.

Fig. 3 is an elevational view partly in section showing a slightly modified form of carburetor 'constructed in accordance with the invention.

Fig. 4 is an elevational view partly in section showing another modification of the invention. p f y Fig. 5 is a sectional elevation of a slightly different form of fuel outlet from the fuel chamber, and

Fig. 6 is a sectional elevation of a portion of a carburetor showing the needle control for the auxiliary jet acting on the nozzle instead of on the fuel chamber outlet.

The invention brieliy described consists of a carburetor having an intake passage adapted to be connected to the intake manifold and a pair of fioat chambers adapted to furnish fuel to the nozzle or nozzles which have their outlet in a restricted portion of the intake passage. The float chambers are connected by a restricted 'passage through which fuel passes from the main or large float chamber to a smaller or auxiliary chamber and means is provided for controlling the outlet of fuel from the auxiliary float chamber in such a manner that a rich mixturewill be furnished for acceleration purposes but the mixture will be automatically gradually `cut down as the engine is speeded up and is running at high speed. In certain forms of the invention illustrated a float in the auxiliary float chamber has secured thereto an elongated tapered needle which acts as a valve and controls the area of the outlet opening from the auxiliary float chamber to the carburetor nozzle. In another form of the invention the float controlled valve operates directly on the auxiliary nozzle or jet.

Briefly stated, the needle valve permits {arelatively large volume of fuel to flow to the carburetor nozzle when the engine is opened up but the efflux of this relatively large volume of fuel causes the float to fall carrying with it the needle valve thereby automatically restricting the outlet opening from the auxiliary oat chamber. Thus when the engine is opened up or accelerating, a rich mixture is furnished but immediately thereafter the mixture is made leaner by reason of the decrease in the outlet opening from the auxiliary float chamber. Further details of the invention will appear from the following description.

In the embodiment of the invention illustrated in Fig. 1, the carburetor comprises a main float chamber 10, an auxiliary float chamber 11, an intake conduit 12 having a Venturi passage 13 and an air inlet 14. A throttle valve 15 of the usual butterfly type is mounted on the conduit 12.

The main float chamber 10 is of the usual construction and has a cover 2O provided with an air bleed opening 21. A fuel intake pipe 22 leads into the bottom of the float chamber 10 and is controlled by a needle valve 23. The valve 23 has a grooved disk 24 secured thereto and arms 25 which are pivoted on fixed pivots 26 in the usual well known manner, engage the disk 24 attheir inner ends and at their outer ends have formed thereon balls 27 which rest on the upper surface of the float 28 which is vertically movable in the ioat chamber on the member 23. This construction is old and common and, therefore, has not been shown in detail.

In the form of the invention illustrated in Fig. 1, the oat chamber 10 is connected by a conduit 30 to a nozzle 31, the outlet end of which is disposed in the restricted portion of the Venturi passage 13.

The auxiliary fioat chamber 11 receives fuel from the main float chamber 10 through a restricted connecting passage or conduit 32 and when the engine is not running the level of the fuel in the auxiliary ioat chamber will be the same as the level in the main float chamber. A cover 35 is secured to the upper end of the auxiliary float chamber 11, and has a bleed opening 36 therein and a boss 37 extending downwardly therefrom. A Iioat 3S is mounted in the float chamber 11 and has an upwardly extending guiding stem 39 which extends through the boss 37. The float 38 also has secured thereto and extending downwardly therefronr an elongated tapered needle 40 which is adapted to enter a tapered outlet opening 41 formed in the lower end of the auxiliary oat chamber 11. The opening 41 is connected by a conduit 42 to a nozzle 43, the outlet end of which is positioned in the restricted portion of the Venturi passage 13.

The construction shown in Figs. 1 and 2 operates as follows. As above stated, the normal level of the fuel in both of the iioat chambers will be the saine. When the engine is speeded up or accelerated, a relatively large volume of fuel will be permitted to pass through the outlet opening 41' of the float chamber 11 thereby providing a rich mixture for the acceleration. As this fuel rapidly passes out of the Hoat chamber 11, and is drawn out faster than the fuel will flow in through the restricted opening 32, the iioat 38 and with it the needle valve or needle 40 will fall thereby partially closing the passage 41 through which the -fuel passes into the conduit 42 to the nozzle 43. Since the outlet passage from the auxiliary float chamber is thus restricted, the volume of fuel passing from the auxiliary float chamber will be decreased and the running mixture will be leaner than the acceleration mixture, which is desired.

ln the embodiment of the invention shown in Fig. 3, the auxiliary ioat chamber 11 is connected by a conduit to the conduit 30A which leads from the main ioat chamber 10. By reason of this construction, the fuel from the auxiliary iioat chamber and the fuel from the main float chamber will pass to a common nozzle 31A. Moreover, when the engine is throttled down after acceleration, the auxiliary float chamber will be reilled through the conduit 50 as well as through the passage 32.

In Fig. 4 the auxiliary float chamber 11 is connected to a conduit 55. rlhis conduit communicates with a passage or conduit 56 which discharges into the restricted portion of the Venturi passage 13 and the conduit 55 also has its upper end connected to a passage 'i 57 which discharges into the intake conduit 12 at a point opposite the portion 58 of the throttle valve 15 when the valve is in its closed position. A notch 59 is formed in the throttle valve in a position to register with the opening 57 thereby permitting the mixture from the conduit 55 to pass to the engine when the engine is throttled down. Y

Vith the construction shown in Fig. 4, the passage 56 receives fuel during the acceleration thereof, this passage being controlled by the needle valve 40 in the same manner as the auxiliary nozzle 43 shown in Fig. 1. When the engine is throttled down, however, as shown in Fig. 4, the mixture passes from the conduit 55 through the passage 57 to the engine and air will pass into the conduit 55 through the passage 56.

F 5 illustrates a slightly different form of outlet nozzle for the fuel chamber 11. As shown therein, the fuel discharge opening 60 is substantially cylindrical and has communicating therewith a downwardly inclined fuel discharge passage 61 which is disposed at the bottom of the chamber 11. With this form of construction when the engine is started and a rich mixture is desired, fuel will pass to the conduit 42 through the discharge opening 60 and also through the passage 61. As the engine accelerates and is running at higher speed, the needle valve 40 will gradually decrease the area of the discharge opening 60 until the upper end of this discharge opening is closed and the fuel for the passage 42 will then be drawn entirely through the passage 61 which will furnish sufficient fuel in conjunction With the fuel supply from the main float chamber for the operation of the engine under running conditions.

F ig. 6 illustrates another embodiment of the invention in Which the float 38 in the auxiliary fuel chamber Vl1 is connected to the needle control valve 65 through a series of levers, the valve 65 operating directly in the auxiliary fuel nozzle or jet 433. The control valve 65 is guidedin a bracket 66 and is connected at its upper end by a pin and slot connection 67 to a lever 68 pivoted at 69. The opposite end of the lever 68 is connected by a link 70 to a lever 7l, pivoted at 72 to a lug 7 3 mounted on the cover 35 of the auxiliary fuel chamber. The opposite end of the lever 7l is connected by a pin and slot connection 74 to the upper end of the stem 39 Which is carried by the float 38. Y

`With the construction shoWn in F ig. 6, When the engine is started the float 38 Will be disposed in elevated position and the valve 65 Will permit a relatively large amount of fuel to pass through the nozzle 43. As the engine is speeded up and reaches its running speed, the float Will gradually drop thereby through the levers 71 and 68 causing the control valve 65 to decrease the area of the opening in the out-let or discharge end of the auxiliary jet or nozzle 43.

From the foregoing specification, it Will be seen that a simple and practical form of carburetor has been designed and that a carburetor constructed and arranged as illustrated Will provide the proper volume and grade of mixture to an engine under all conditions of operation thereof.

Although certain specific embodiments of the invention have been particularly shown and described, it Will be understood that the invention is capable of modification and that changes in the construction and in the arrangement of the various cooperating parts may be made Without departing from the spirit or scope ofthe invention, as expressed in the following claims.

. What I claim is:

l. In combination, a fuel intake passage, a throttle valve therein, a float chamber, a fuel nozzle in said passage and communicating with said float chamber, a fuel chamber communicating With said float chamber through a restricted passage and receiving fuel therefrom, a second nozzle in the intake passage communicating with said second fuel chamber and valve means intermediate the nozzle and fuel chamber for controlling the flow of fuel to said second nozzle.

2. In combination, an intake passage, a

throttle valve therein, a fuel supply chamber chamber, a float in said supplemental chamber, a fuel nozzle in said passage and communicating With said supplemental chamber, and means controlled by the float for automatically controlling the passage of fuel from the supplemental chamber to said nozzle. Y n

3. In combination, an intake passage, a throttle valve therein, a fuel supply chamber communicating directly With said intake passage, a supplemental fuel supply chamber, a float in said supplemental chamber, a fuel nozzle in said passage and communicating With said supplemental chamber, and means including a needle valve controlled by the float for automatically controlling the passage of fuel from the supplemental chamber to said nozzle, said valve being constructed and arranged to gradually decrease the passage of fuel from the supplemental chamber as fuel is Withdrawn therefrom.

In Witness whereof, I have hereunto set my hand this 21st day of October, 1924.

WILHELM B. BRONANDER. 

